The number of women who have achieved pregnancy through the transfer of
frozen embryos has been increasing gradually, according to the Latin
American Network of Assisted Reproduction. The ability to freeze
embryos in assisted reproduction procedure helps women who have trouble
becoming pregnant and those who, for some reason, need to postpone the
moment of becoming mothers. "We achieve a success rate of approximately
30%, which is quite significant, since the Latin American average is
approximately 20%," explains the professor and director of the UFMG
Clinical Origen, Selmo Geber.
With the freeze, the surplus embryos (not transferred) can be
saved for future transfer, without requiring that a woman going through
hormonal stimulation of new procedures or collection of eggs, whether
or not there has been a pregnancy. The freezing may be used if couples
want a new pregnancy.
Freezing
Normally, in a process of assisted reproduction, the patient
produces - under hormonal stimulation - a large number of ova to be
fertilized in the laboratory. To reduce the risk of a multiple
pregnancy, and due to high rates of pregnancy, the doctors of the
Clinic Origen has suggested the transfer of two to three embryos to the
uterus, with the surplus can be frozen for future transfer. Thus it is
possible to reduce the discomfort and risks, and maintain the fertility
of women who chose to become pregnant later or suffering from diseases
that may compromise the ovarian function - as early ovarian failure,
endometriosis, cysts, and pelvic infections and even some type of
cancer.
Another important point is the cost of the procedure, which is
much lower, since there is no need to repeat the use of drugs and
procedures for cycles of in vitro fertilization (test for baby) and
ICSI - Intra-Cytophasmic Injection of Spermatozoa.
The process of freezing, completely developed in Origen, is done
through a computerized program that reduces the temperature of the
embryo progressively from positive 37 degrees Celsius to 196 degrees
below zero. Then, the embryos are stored in liquid nitrogen, which are
for an indefinite period.
One reason for the high rates, in addition to the clinical
experience, is the use of laser technology that allows to make a hole
in the zona pellucida (shell surrounding the embryo) thus facilitating
their implementation. This technique, called assisted hatching is
necessary since the process of freezing can lead to a thickening of the
zona pellucida, which would reduce the possibility of deployment. |